The overall objective of this project is to test the efficacy of an intervention designed to facilitate safe, early return to work after myocardial infarction. The intervention is directed toward improving the confidence (self efficacy) of low risk patients to resume their occupational tasks 3 - 5 weeks after infarction rather than the current standard of 8 - 11 weeks. The intervention has two parts: 1) a treadmill exercise test which demonstrates patients' capacity for occupational work and a thorough explanation of the test (Occupational Work Evaluation) and 2) a Behavior Change Program designed to reinforce patients' confidence in their capacity for occupational work through a 6-month-long program of home-based exercise conditioning, stress management and smoking abstinence. From a clinically low risk subset of 300 previously employed men aged less than or equal to who are medically eligible to perform early exercise testing, half wil be selected to receive the intervention designed to hasten return to work and half will receive usual care. Questionnaires completed by physicians and patients prior to randomization and at specified intervals during the next 6 months will be used to elicit medical, psycholotical, occupational and economic status in participants of the Intervention Trial. The primary endpoint of this trial is the interval between infarction and return to work. Further analyses by multivariate techniques concern the influence of an earlier than usual return to work on medical, psychological, economic and occupational status; determinants of the interval between infarction and return to work; and the economic costs and benefits of the intervention. To determine the potential applicability of the intervention to older patients a Prevalence Survey will be conducted in 300 men aged 61-70 using survey techniques identical to those employed in the Intervention Trial. The major potential benefit of this project is a reduction of disability costs through shortening of convalescence in clinically low risk postinfarction patients. Personnel, facilities and techniques necessary to implement the proposed intervention strategy already exist within the medical care system. Based on an estimated 100,000 previously employed infarction patients eligible to undergo the intervention, each year disability costs could be cut from 1 billion dollars to 500 million dollars--a sum which would repay many times over the modest cost of the intervention.